Surface coating film and process for forming the same

Abstract

A surface coating film coated on a substrate includes at least one member being selected from the group consisting of silicon dioxide and silicon dioxide derivatives, and an additive including polyvinyl pyrrolidone (PVP) being dispersed or solved therein. A forming process therefor includes the steps of applying a coating solution on a surface of a substrate, the coating solution including at least one silicon containing compound, being selected from the group consisting of alkoxy silane, siloxane and organosiloxane, and an additive including PVP, and heating the substrate. Since PVP is dispersed or solved in the surface coating film, it is possible to improve the wear resistance and superficial hardness. Moreover, since the surface coating film is enhanced in terms of the toughness, no crack occurs even when it is formed by polymerization reactions.

What is claimed is:  
     
         1 . A surface coating film coated on a substrate, comprising: 
 at least one member being selected from the group consisting of silicon dioxide and silicon dioxide derivatives; and    an additive including polyvinyl pyrrolidone being dispersed or solved therein.    
     
     
         2 . The surface coating film according to  claim 1  further comprising a primer layer disposed on one of opposite sides of the surface coating film contacting with said substrate.  
     
     
         3 . The surface coating film according to  claim 2 , wherein said primer layer has a thickness of from about 0.1 to about 20 μm.  
     
     
         4 . The surface coating film according to  claim 2 , wherein said substrate is formed of polycarbonate; and said primer layer is formed of at least one member being selected from the group consisting of methacrylic acid-based resins and polyvinyl-based resins.  
     
     
         5 . The surface coating film according to  claim 4 , wherein said primer layer is formed of a methacrylic acid-based resin being made from methylmethacrylate having a polymerizable unsaturated group by polymerization.  
     
     
         6 . The surface coating film according to  claim 1  having a thickness of from about 0.5 to about 20 μm.  
     
     
         7 . The surface coating film according to  claim 1 , wherein said polyvinyl pyrrolidone has a molecular weight of from about 40,000 to about 360,000.  
     
     
         8 . The surface coating film according to  claim 7 , wherein said polyvinyl pyrrolidone has a K-value of 30.  
     
     
         9 . The surface coating film according to  claim 1 , wherein said polyvinyl pyrrolidone is included in an amount of from about 1% to about 20% by weight.  
     
     
         10 . The surface coating film according to  claim 9 , wherein said polyvinyl pyrrolidone is included in an amount of from about not less than 1% to about less than 15% by weight.  
     
     
         11 . The surface coating film according to  claim 9 , wherein said polyvinyl pyrrolidone is included in an amount of from about not less than 1% to about less than 10% by weight.  
     
     
         12 . A process for forming a surface coating film, comprising the steps of: 
 applying a coating solution on a surface of a substrate, the coating solution including at least one silicon containing compound, being selected from the group consisting of alkoxy silane, siloxane and organosiloxane, and an additive including polyvinyl pyrrolidone; and heating the substrate.    
     
     
         13 . The process according to  claim 12 , wherein a primer layer is formed on a surface of said substrate in advance.  
     
     
         14 . The process according to  claim 12 , further comprising the step of: 
 applying to the substrate surface a primer layer prior to the application of the coating solution, whereby the coating solution is applied over the primer layer.    
     
     
         15 . The process according to  claim 12 , wherein said silicon containing compound is a multi-functional silicon containing compound having four or more functional groups.  
     
     
         16 . The process according to  claim 12 , wherein said coating solution has a solids content of from about 5% to about 40% by weight.  
     
     
         17 . The process according to  claim 12 , wherein the substrate is heated at a temperature of from room temperature to about 150° C.